Definition: In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
Input: ['9473', 'z', '4835', 'j', 'e', 'b', '6031', '5553']

b, e, j, z